ignore vim swap files

From: https://github.com/github/gitignore/blob/main/Global/Vim.gitignore

Author: jtriley

.gitignore

@@ -127,3 +127,10 @@ dmypy.json
 
 # Pyre type checker
 .pyre/
+
+# vim swap files
+[._]*.s[a-v][a-z]
+[._]*.sw[a-p]
+[._]s[a-rt-v][a-z]
+[._]ss[a-gi-z]
+[._]sw[a-p]